Vertical axis gyratory screen



' VERTICAL AXIS GYRATORY SCREEN Filed June 6, 1952 6 Sheet s-Sheet l lare Sywaie' im #QQ/@L Sept- 24, 1957 L. G. sYMoNs 2,807,367

.VERTICAL AXIS GYRATORY SCREEN Filed June 6, 1952 6 Sheets-Sheet 2 Invenzionilre 'dlfyzozas' @fw #4A/l,

Sept. 24, 1957 L. G. SYMONS 2,807,367

VERTICAL AXIS GYRATORY SCREEN Filed June 6, 1952 6 Sheets-Sheet 3 fifa/"Heya Sept- 24, v1957 l., G. sYMoNs 2,807,367

. VERTICAL Axrs GYRATORY SCREEN Filed June s, 1952 e Sheets-sheet 4 fait?? @KLS Sept 24;' 1957 G. `sYMoNs v 2,807,367

VERTICAL Axrs GYRATORY SCREEN Zar 7? .Syzwof/eus Sept. 24, 1957 L. GfSYMONS -VERTICAL AXIS GYRA''ORY SCREEN 6 Sheets-Sheet 6 T22 are fahr Zaren .S'ymzs Patented Sept. 24,1957

VERTICAL Axis GYRATORY SCREEN Loren G. Symons, Hollywood, Calif., assig'nor to Nordberg Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Application .lune 6, 1952, Serial No. 292,106 Claims.` (Cl. 209-301) Y This is a continuation-in-part of application Serial No. 149,721, filed March l5, 1950, now abandoned.

My invention relates to an improvement in screens and has for one object an improved rotary-gyratory screen of maximum capacity.

Another object is a screen of the rotary-gyratory type of maximum strength.

Another object is an improved means for supplying and removing the screen medium'or mesh of a rotary screen.

Another object is an improved rotor for rotary screens of the gyrating type.

Another object is an improved driving means for a rotary screen.

Another object is a new and improved sealing sleeve to seal effectively the improved rotor from any of the material being screened.

l illustrate the invention more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a perspective view with parts broken away;

Figure 2 is a vertical section;

Figure 3 is a section along the line 3 3 of Figure 2, with the parts in position for the application of new medium to the screen;

Figure 4 is a section similar to Figure 3, with the medium in position on the screen;-

Figure 5 is a section on an enlarged scale along the line 5-5 of Figure 2;

Figure 6 isa partial vertical section on an enlarged scale alongthe line 6-6 of Figure 4;

Figure 7 is a section along the line 7--7 of Figure 6; and

Figure 8 is a vertical section of a modified form of rotor similar to the one in Figure 2.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, 1 generally indicates a suitable support or base herein shown as a table having a plurality of supporting legs 1a. A hopper 3 is supported from the base of the table and is shown as having abottom discharge outlet 4, which may be associated with or deliver to any suitable receiving element, conveyor or the like. Mounted on the table or base 1 are side plates 5,` having flanges k6, which surround or define openings closed by removable closure membersk 7. The closure members 7 may be held by any suitable means, such as latches 8. It will be understood that when the front and back closure members 7 are removed, access is readily had to both sides of the screen rotor to be described hereinbelow.

9 is any suitable top member extending between the flanges 6, having an aperture 10. 11 is any suitable hopper. Positioned above the top portion 9 is a support or bracket 12, best shown in Figure 2, upon which is mounted a motor 13 with its pulley 14. The bracket or support 12 includes a supportingor positioning ringv or flange 15, in Whichis positioned 'an annular pad or support 16 of flexible material, such as rubber or a suitable rubber substitute. 17 is a top element resting upon the pad 16 and carrying any spider elements or other suitable elements 18 secured to or unitary with an inner sleeve 19. The sleeve 19 is shown with a downwardly extending portion 24 at the lower end of which is an additional bearing assembly 26. 27 indicates an out- Wardly extending pinion gear mounted on or xed in relation to the sleeve extension 24.

It will be understood that the above-described structure rests yieldingly upon the pad 16, but is suitably held against rotation.

Extending downwardly from the elements 18 is the ring or sleeve 28 constituting, as will later appear, a bearing for the sealing ring 29 at the upper end of the cylindrical flexible sealing sleeve 30.

A generally indicates a screen actuating rotor structure, which includes cccentrically axised portions 34 and 37. The upper portion 31 rotates concentrically with the bearing assemblies 23, 2S and 26, and carries at its upper end the driven pulley 32, about which pass the driving belts 33, whereby rotation of the motor 13 is effective to rotate the shaft 31.

An intermediate portion 34 of the shaft is eccentrically offset, its axis being shown in the position of the parts of Figure 2, as displaced tothe right of the axis of the shaft portion 31. Thus it will be understood that as the shaft rotates, the portion I34 will tend to gyrate any element surrounding its exterior surface. The lower portion 35 of the shaft may be formed concentrically with the upper portion r31, but it is provided with an unbalanced weight 36. Its lower end, as at 37, is provided with an eccentric portion concentric with the upper concentric portion 34. The shaft structure, as a whole, is supported from above, as will be clear from Figure 2, being, in effect, flexibly suspended from the upper support orbracket 12 by means of the supporting ring or flange 17 and its associated parts.

Surrounding the shaft is a screening drum or rotor which, by the above rotor structure, is simultaneously rotated and gyrated. It is shown as including a central sleeve or housing generally indicated at 40. The housing includes an upper plate 41 with a central sleeve 42 within which is the lower bearing assembly 43 and theV upper multiple roller bearing assembly 44. Secured to and extending upwardly above the plate 41 is a conic extension 47, which terminates in aninternally toothed ring gear 48 in mesh with the externally toothed pinion gear 27. As will be clear from Figure 5, the two gears are of different diameters and have an unequal number of teeth. The lower edge of the sealing member or sleeveY l without access of dust to the interior of the housing 40.

The housing 40 has its lower end secured to a bottom assembly 50 in which it is positioned a multiple rotor bearing assembly 51 which receives the bottom eccentric shaft portion 37.

It will be understood that the result of the rapid rotation of the above-described shaft is to impart both gyrotory and rotary movement to the housing 40 and to the parts connected to it.

In the structure of the screen, I provide a generally cylindrical screening medium shown at B in Figure 2.

It is important that this medium be firmly positioned and.

provide 'an approximately cylindrical surface. It is also important that it will be applicable to and removable from the screen structure with a minimum of diiculty and at maximum speed. While a'wide variety ofrotor structures can be` employed, I find the structure herein shown allowing removal and replacement ofk theV screen .to be particularly strong and eicient. t

Treating the housing 'member 4.0 as the inner member of the rotor, I employ a system of radial ribs '60, 61 shown in Figure 2 extending 'outwardlytherefrom- The lower ribs are shown as associated 'with a centralplate 62, having' a downwardly extending `oil sump 63, from which the ribs 60 radiate. The linterior of the'sump63 is accessible through `the 4tubeor fitting 64, closed by the removable threaded plug 65. lThe plate 62 Vmay be bolted or otherwise secured tothebottom 'sump or closure 50 of the housing-40. The upper 'radiating ribs 61 are shown as associated with the deflecting member or members 66 aligned to receive ffeed fromfthehopper 11 through the aperture and to deliver itee'ntrifu'gally outwardly and slightly upwardly against the receiving drum portion 67 at its top cover 68. The deectingmembcr is mounted upon arms 69 ofa spider'secured to the housing 40.

Secured `to the upper and lower ribs 460 and 61 are vertical channels '70, `shown as Varranged in pairs, back to back, as willbe clear forexamp'le from Figure 3. Extending outwardly `from the chanels 70 are radial extensions 71, which receive rings 72, 4see IFigure 4. These rings are shown as adjustablyconnected -by'the employment of threaded elementsl73. The mesh'ormedium, as shown in Figure 3, may be `woundonto `the drum thus formed and is firmly supported from `within by the rings 72. It is held against the exterior ofthe rings as follows: Two upright pipes or sleeves 75 -are suitably secured to the screen rotor at their Vupper'and lowertends, as for example, in Figure 6, `to brackets 76 and drum portion 67 and to the T-shaped ring 77 which is carried by extensions 60a of arms .60. Each pipe carries spaced therealong fixed plates 78 lat either end'and plates 78a arranged in pairs and welded orotherwise Ysecured to the tubes. Pivoted or secured Ato and between the two `tubes 75 as shown :in Figure l3, .are clamping ring Asegments 79, which carry the clamping segments proper 80, `which may be formed of rubber or a rubber substitute and 4which are channeled to receive vthe `inner edges ofthe-ring segments 79.` Pivoted to each1ofpairs of rplates 78a, and extending away from intermediate segment portions 79 and 80, are `the free-ended segments 81,#82, each with its channeled clamping segment 83 or 184 of rubber `or suitable rubber substitute. The members 181 are shown as carrying locking elements or screws 85 at their free ends, which mate with corresponding locking A,elements 86 at the free ends of segments 8410 be locked bya locking member 87.

As will be clear for example from-Figure 6, the clamping segmental pads `80, `83 and 484 are all aligned with the interior clamping rings 72, `whereby when the iparts are in the locked position in -which theyare shown in Figure 4, the medium ris firmly clamped in relation to the other parts of'lthe rotor. However, the medium can quickly be removed and replaced by merely releasing the locking member .-87 `and moving the clamping rings to the position in which they are shown in Figure 3.

The 4whole medium .can :then :readily Vbe` removed from i the drum and the new` medium wound thereupon, cut to length `and then clamped tin position. The ends of the medium may be clamped Atogether by any suitable means, diagrammaticallyindcatedLat X=in` Figure 4.

The clamping structure above referred to is `made of three segments. The lsection, including clamping ring segments `79,` vupright pipes V'75 and attached plates 78, may be moved tothe position of Figure 3, for replacing medium B, by loosening the bolts 90 which extendthrough slots 92 inthe brackets76-and the ange ofthe T-shaped ring 77. lIt will be `noted that theclamping ring segments 79, 81 and 82 are held `improper spacing alignment `by attached angle members `93 which are bolted to vertical supporting bars 94.`

The modification disclosed in Figure 8 represents a slightly different `type of driving mechanism from the one shown in Figure 2. In `this embodiment, as before, the entire drum unit is suspendedfrom `the base by a top element or plate 201 through an annular pad or support 202 of flexible material. Thetop element is provided with a depending skirt 203 that has in-turned flanges 204 so as to present an opening 205 through which the main drive mechanism may be inserted. Drive shaft 206 is of the same general characteristics as in the prior embodiment. Shaft 206 is mounted and supported in a hanger box 207 that is detachably connected to the top plate 201 through any conventional means, such as bolts 208. The upper portion of the hanger box is provided with a cylindrical bearing housing 209 that encloses and supports upper bearing unit 222. The lower portion of the hanger box is adapted to mate with and provide an effective sealing ,surface for a resilient accordian type cylindrical seal 210. As in the prior embodiment of Figure 2 the lower portion of the seal 210 is connected to the youter surface oftheringgear 211 so that the seal will rotate with 'the drum yand ring gear when they are rotated and gyrated by shaft 206 andits associated mechanism. The upperportion-of the seal 210 is connected to a sealing ring 212 that rotates with the seal and consequently with the drum. This ring 212 also functions as a housing fora ball `bearing 213, the outer race of which rotates with the sealing ring, while the inner race firmly `engages land remains stationary with the hanger box 207. This bearing is positioned against a shoulder on 'the hanger box by an upstanding casing 214 extending up from the pinion 215. The pinion 215 with its upstanding casing 214 is detachably connected to the hanger means `such as bolts 216 sothat the hanger box and casing can be drawn telescopically together so `as to trap and iirmly seat .the inner :race of the ball bearing 213 between them.

With this `type lof Vconstruction the seal 210 does not support any of its upper sealing parts, such as the sealing ring 212, and the sealcan be formed of any material that is found to be suited vfor sealing purposes in this type of structure without regard to "its Avertical compressive strength.

Ring gear 211 and a housing 217 for the eccentric bearing unit 224 are ltormedas an-integral unit. Flanges 218 extending outwardly from the ring gear and bearing housing lprovide a portion -to which the side sections of the drum structure may be connected. In this ltorm, the ring vgear 2111,eccentricfbearinghousing 217, and drum supporting ange 218 are cast and machined as an integral unit.

As an additional means 5for sealing off the numerous bearings around the upper portion of the shaft from any dust particles that have strayed from the screening operation and for protecting the pinion and ring gear, an upstanding gear guard 220 is supported and bolted to ange 218. This guard `will rotate and gyrate with the drum, and its upper'portion very closely approaches the non-rotating, inturned ange 204 of the skirt 203. The combination of the stationary skirt 203 and the moving guard 220 also forms a 'protection for the seal 210 so that it cannot be lstruck and. damaged by larger pieces of material that have ricocheted away from the surface of the screen drum.

It will be -realizedthat, whereas, I have described and illustrated a practical and operative device, nevertheless many changes may be made 'in 'the size, shape, number and disposition of parts without departingfrom the spirit of my invention. I therefore wish my description and drawings to tbe taken as is `a broad sense illustrative or diagrammatic, rather than `as limitingmeto my specific disclosure.

The use andoperation of my `invention are as follows:

I provide .a simple, t compact `screen `structure in which, in `response to rotation .of the unbalanced rotor A,.a predetermined relation between rotation and gyration is maintained. The rotor is entirely suspended from above, there being no bearing parts below or aligned bearings to be lubricated or to wear. In Figure 2 the bearings are completely housed with a housing system, which includes the rotating drum, the flexible sealing sleeve 30, which rotates with the drum, and the fixed structure 19, 28, etc. The ring 29 rotates about the exterior of the normally fixed flange 28. In Figure 8 these same parts in addition to being enclosed by a similar sleeve 210 are also surrounded and protected by the depending skirt 203 and upstanding gear guard 220.

Any suitable fitting for applying grease or lubricant may be employed. For example in Figure 2, I illustrated a fitting 100 for the bearing surface between the rings 28 and 29, a fitting 101 for the space above the meshing teeth 27 and 48, and a fitting 102 for the space within the sleeve extension 24, whence the lubricant can penetrate to the bearing systems 26 and 44. The bearings 23 and 25 can be lubricated through the fitting 103. The interior of the housing 40 may receive lubricant from Cil above or the bearings 51 may be lubricated through the individual fitting 104. Excess or used lubricant or grease may be removed by removal of the bottom plug 65. None of the moving parts are accessible to dust or dirt from outside.

The result of the rotation of the shaft A, with its eccentric portions, is to impart simultaneous rotation and gyration to the medium B. The proportion and number of the teeth may be set to obtain the desired relationship between rotation and gyration. The particles to be screened are centrifugally fed over the feed portions 66 and travel downwardly within the medium. Each typical particle, owing to the rotation of the screen at suitable speeds tends to be conveyed to the inner surface of the medium B, the speed of rotation being effective to urge the particles outwardly into contacting relation with the mesh. On the other hand, the gyration of the mesh withdraws the medium B outwardly away from the particles, so that as they move through the screen, they are delivered more or less tangentially outwardly when the mesh withdraws at the beginning of gyration, being again picked up by the mesh when the mesh returns at the end of gyration. This characteristic action is fully described in my application Serial No. 538,788, led lune 5, 1944, and now Patent No. 2,500,965.

In the particular drive herein shown in Figure 2, I employ a pinion gear 27, which is fastened to and forms part of the spider or support 18. The internal gear 48 is fastened to and is part of the screening drum structure above described. The same is true of the pinion gear 214 and internally toothed ring gear 211 in the modification shown in Figure 8. In the operation of the machine herewith shown, the `difference in the pitch diameter of the pinion gear and the internal gear is twice the eccentricity or equal to the one-half inch throw of the machine. Under these conditions and with the parts as shown, the shaft eccentric A Will move the external gear 48 progressively around in contact with the pinion gear 27. In the particular design herein shown, the pitch diameters of the two gears bear the relationship of 13 to 14 to maintain 14 gyrations of the screen surface to each rotation. It will be understood, of course, that to obtain a different relationship, the parts must be differently designed or proportioned.

I claim:

1. In a rotary-gyratory screen, a base, a screen drum, and means intermediate the base and the drum for suspending the drum from the base and simultaneously rotating and gyrating the drum with a predetermined relationship between rotation and gyration, including a pinion non-rotatively mounted with relation to said base, and an internally toothed ring gear non-rotatively mounted with relation to said drum in meshing engagement with said pinion, the drum and base constituting two elements, a flexible tubular seal extending between the two elements, and a slidable connection between' one end of the seal and one of the elements.

2. In a rotary-gyratory screen, a base, a screen drum, and means intermediate the base and the drum for suspending the drum from the base andfor simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and to cause gyration of the drum as the shaft is rotated, a pini-on non-rotatably mounted in relation to said base, and an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said ldrum so as to cause rotation of the drum as the same is gyrated.

3. In a rotary-gyratory screen, a base, a screen drum, and means intermediate the base and the drum for suspending t-he drum from the base and for simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and to cause gyration of the drum as the shaft is rotated, and a pinion non-rotatably mounted in relation to said base, an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to the drum so as to cause rotation of the drum as the same is gyrated, the pitch diameter of the internally toothed ring gear exceeding the pitch diameter of the pinion, the difference between the pitch diameters being twice the eccentricity of the eccentric components.

4. In a rotary-gyratory screen, a base, a screen drum, and means intermediate the base and the drum for suspending the drum fnom the base and for `simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and to cause gyration of the drum as the shaft is rotated, a pinion non-rotatably mounted in relation to said base, an internally toothed-ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause rotation of the drum as the same is gyrated, and a flexible seal extending between theV drum and the base non-rotatively mounted at one end on the drum and rotatively mounted at the other end on the base, the mounting on the 'base including a sealing ring on the flexible seal and a circular' flange on the base engaging said ring in dust-sealing relationship.

S. In a rotary-gyratory screen, a base, a screen drum, and means inter-mediate the base and the drum for suspending the drum from the base and for simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and to cause gyration' of the drum as the shaft is rotated, a pinion non-rotatably mounted in relation to said base, land an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause rotation of the drum as the same is gyrated, the eccentric bearing connections being formed as separate units from the internally toothed ring gear.

6. In a rotary-gyratory cylindrical screen, a base, a screen drum, and means intermediate the basey and the drum for suspending the drum from the base and for simultaneously rotating and gyrating the entire drum, said means including a shaft extending within said drum, said ahaftz'having eccentric components positioned `therealong within said drum and being rotatably mounted from said base, eccentric bearing Aconnections between the eccentric components and the upper` and lower portions of the drum formed and adapted to `support the drum on the shaft and to lcause gyration of the entire drum as the shaft is rotated, a vpinion non-rotatably mounted in `relation to said base, an internally toothed ring ygear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause .rotation of the drum as the same is gyrated, the ring gear being provided integrally with a depending housing for the eccentric bearing connections within said 4drurn and with an outstanding flangefto supportthe screen drum, and power means for rotating the shaft.

7. In a rotary-gyratory screen, a base, a screen drum, means intermediate the base and the drum for suspending the drum from the base and for simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric `components and the drum formed and adapted to supportthe drum on the shaft and to cause gyration of the -drum as the shaft is rotated, a pinion non-rotatably mounted in relation to said base, an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause `rotation of the drum as it is gyrated, a llexible seal extending between the drum and the base, the seal including an upper portion extending thereabove, a sealing ring positioned between the upper portion of the seal and the base, `the sealing ring being dctachably secured to the seal, a ball bearing unit intermediate the sealing ring and the base, and power means for rotating the shaft.

8. In a rotary-gyratory screema base, a screen drum, means intermediate the base and the drum for suspend ing thedrum from the base and for simultaneously rotating `and gyrating the drum, said means including a shaft witheccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and to cause gyration of the drum as the shaft is rotated, a pinion non-rotatably mounted in relation to said base, an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause rotation of the drum as the same is gyrated, a ilexible seal extending between the drum and the base, a ball bearing unit interposed between one end of the seal and the base so as to provide for relative motion there between, and power means for rotating the shaft,

9. In a `rotary-gyratory screen, a base, a screen drum, means intermediate the base and the drum for suspending the drum from the base and for simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentricl components and `the drum formed and adapted to support the drum on the shaft and to cause gyration of thedrum as the shaft is rotated, a pinion non-rotatably mounted in` relation to said base, an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause rotation of the drum as the same is gyrated, a flexible tubuiarseal surrounding said shaft adjacent said pinion and ring gear to seal the same against dust, a cylindrical skirt depending from the base, a cylindrical gear guard upstantling from the outer portions ofthe ring gear, the lower-most portion of the skirt and the upper-most portion ofthe guard being contiguous, the skirt and guard being adapted and arranged to enclose and protect the exibie tubular seal against impact of material being fed toisaid screen, and power'means for rotating the shaft.

10. In a screening structure, a base, a generally cylin- 7 drical screen drum movably supported on said base, a drivingtassembly formed andadapted simultaneously to gyrate and rotate said drum, said driving assembly including a generally .upright drive shaft and ,a vdriving connection therefore, said driveshaft being supported on `said base, said drive shaftincluding a lower eccentric portion, and a driving connection for saididrum adapted to rotate the same in response to the gyration imparted thereto by the rotationof the driving connection including a pinion non-rotatably mounted with respect to said base and an internally toothed ring "gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum, so as to establish a lixed predetermined relationship between the yrate of rotation and `the rate of gyration.

11. In a supporting and driving assembly for a rotary gyratory screen drum, a top element formed and adapted for suspension `from `a suitable base, an upper and a lower bearing Vassembly vertically spaced therein, a vertically .axiscd shaft rotatable in said bearing assemblies, said shaft `having additional axially spaced, eccentric bearing surfaces located below said `lower bearing assembly, said shaft being counterweighted, said eccentric bearing surfaces being described `about an axis parallel with the axis of the `first :mentioned first and second bearing assemblies, `but eccentric thereto a `drum structure rotatably positioned about said eccentric shaft, bearing assemblies between vertically spaced portions of said drum structure and said eccentric ybearing surfaces, said drum struc* ture including 4an internally toothed ring gear, said top element rincludingzan externally toothed gear of less pitch diameter than said `ring gear, and in mesh therewith.

12. The structure of claim 11 characterized by and including a flexible, tubular `sealing element extending from an upper portion of the drum structure to an upper portion ofthe top element, said sealing assembly having an upper sealing ring iin rotatable sealing relation with an opposed portion of said top element.

13. The structure of claim 1l characterized by and including a flexible, tubular sealing element extending from an upper portion of the drum structure to an upper portion of the top element, said sealing assembly having an upper sealing ring in rotatable sealing relation with an opposed portion :of said top element and an anti-friction bearing within said upper sealing ring and between it and a downwardly extendingiportio'n of the top element.

14. In a rotary-gyratoryscreen, a base, a screen drum, means intermediate the base and the drum for suspending the drum from the base and for simultaneously `rotating and gyrating the drum, said means including a shaft with eccentric components `therealong rotatably mounted from said ybase, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and `to cause gyration of the drum as the shaft is rotated, a pinion non-rotatably mounted in relation to said base, an internally toothed ring gear in meshing engagement with said pinion and non-rotatably mounted in relation to said drum so as to cause rotation of the `drum as lit is gyrated, a flexible seal extending between the drum and the base, the seal including an upper portion extending thereabove, a sealing ring positioned between the `upper portion of the seal and the base, the sealing ring being detachably `secured tothe seal, a ball bearing `unitiintermediate the sealing ring and theibase, an opstanding casing on the pinion surrounding a portion of the shaft and abutting the ball bearing unit, a shoulder on the base, the ball bearing unit being positioned between the upstanding casing on the pinion and the shoulder, and power means for rotating the shaft.

15. In a rotary-gyratory screen, a base, a screen drum, means intermediate the base and the drum for suspending the drum from the base and for simultaneously rotating and gyrating the drum, said means including a shaft with eccentric components therealong rotatably mounted from said base, eccentric bearing connections between the eccentric components and the drum formed and adapted to support the drum on the shaft and to cause gyration of the drum as the shaft is rotated, a pinion non-rotatably mounted in relation to said base, an internally toothed ring gear in meshing engagement with said pinion Aand non-rotatably mounted in relation to said drum so as to cause rotation of the drum as it is gyrated, a exible seal extending between the drum and the base, the seal including an upper portion extending thereabove, a sealing ring positioned between the upper portion of the seal and the base, the sealing ring being detachably secured to the seal, a ball bearing unit intermediate the sealing ring and the base, an upstanding casing on the pinion surrounding a portion of the shaft and abutting the ball bearing unit, a shoulder on the base, the ball bearing unit being positioned between the upstanding casing on the pinion and the shoulder, a cylindrical skirt v depending from the outer portion of the housing, a cylindrical gear guard upstanding from the outer portions of 10 the ring gear, the lower-most portion of the skirt and the upper-most portion of the guard being contiguous, the skirt and guard being adapted and arranged to enclose and protect the flexible seal and the pinion and ring gear, and power means for rotating the shaft.

References Cited in the le of this patent UNITED STATES PATENTS 463,162 McCully Nov. 17, 1891 964,183 Prescott July 12, 1910 2,134,876 Hull et a1. Nov. l, 1938 2,198,148 Baily Apr. 23, 1940 2,367,070 Symons Ian. 9, 1945 2,500,965 f Symons Mar. 21, 1950 FOREIGN PATENTS 36,841 Switzerland Apr. 26, 1906 432,848 Great Britain Aug. 2, 1935 595,580 Great Britain Dec. 9, 1947 

